Interventionless Packer Setting Tool

ABSTRACT

A packer setting mechanism has a series of fingers with tabs protruding into the mandrel bore. An object such as a plug is landed on the protruding tabs and pressure is applied. The fingers extend from a ring whose movement triggers the packer to set by driving out slips on cones and compressing a sealing element. When the packer set, tensile stress builds in the fingers and a reduced dimension location on the fingers just above the tabs pulls apart. The plug drives the fingers outwardly by pushing them along a ramp against an opposing spring force. The plug clears the tabs as the tabs are driven outwardly on respective ramps such that the tabs are precluded to enter the bore as the plug clears. The drift dimension in the mandrel is preserved when the plug clears.

FIELD OF THE INVENTION

The field of the invention is packers and more particularly packers thatare set with mechanical compression triggered by pressure applied to alanded plug on the setting mechanism with the plug advancing out of thepacker after setting.

BACKGROUND OF THE INVENTION

Packers are downhole barriers used in a number of applications toisolate portions of a borehole. They can be set with setting tools thatcreate relative axial movement to axially compress a sealing element andassociated slips such that those components extend radially to a sealingposition with the slips anchoring the set position of the sealingelement. The slips are frequently driven out radially on cones or rampsassociated with the mandrel body of the packer. The extended or setposition for the packer components can also be locked in with body lockrings or snap rings or dogs in grooves to name a few options. If thepacker is to be retrieved, the locking mechanism can be defeated,generally with an upward pull on the packer mandrel through a connectedtubular string or by way of a release tool run into the packer on aretrieval string. Some packers can also be released with cutting themandrel to overcome the locking mechanism. The setting tools that createrelative movement generally are of the type that hold a grip on themandrel while pushing down a setting sleeve to ramp out the slips andaxially compress the sealing element to increase its diameter so that aseal is obtained. These relative movement setting tools are driven bydeveloped gas pressure such as by a chemical reaction and are releasedfrom the packer as part of the setting movement as a result of parting aretainer that allowed the setting tool to properly position the packerin the borehole.

Other packers can be set with tubing pressure acting on differentialpiston areas or one side of a piston to achieve axial compression of theassembly of slips, cones and sealing elements to obtain the setposition. Another type of packer can hold a caged ball such thatpressure from above seats the ball and drives a piston to compress thepacker components for a set. The problem with these designs is that thebore through the packer is impeded for flow as the caged ball isdisplaced off its seat while retained in the cage as produced fluid hasto flow around the caged ball. Other tools cannot pass the caged ball,precluding intervention beyond the packer. One example of this design isU.S. Pat. No. 6,394,180. Inflatable packers are set with tubing pressuregoing through a valving system and into an enclosed volume. Usually oneend of the inflatable is free to move and rides up closer to the fixedend as the inflatable grows in radial dimension at a center location forthe seal. Still other types of packer are set with reaction to wellfluids or their temperature. The sealing element can be a swellingmaterial or a shape memory foam for example.

What is needed and provided by the present invention is a way to set apacker quickly while still leaving the drift diameter of the borethrough the packer intact. The setting mechanism is equipped to detainan object on which pressure can be developed to create the compressiveforce needed to set the packer. As the packer sets components of thesetting system separate and retract from the mandrel passage allowingthe object to pass leaving the drift dimension intact for operationsthrough the packer. These and other aspects of the present inventionwill be more readily apparent to those skilled in the art from a reviewof the detailed description of the preferred embodiment and theassociated drawings while recognizing that the full scope of theinvention is to be determined form the appended claims.

SUMMARY OF THE INVENTION

A packer setting mechanism has a series of fingers with tabs protrudinginto the mandrel bore. An object such as a plug is landed on theprotruding tabs and pressure is applied. The fingers extend from a ringwhose movement triggers the packer to set by driving out slips on conesand compressing a sealing element. When the packer set, tensile stressbuilds in the fingers and a reduced dimension location on the fingersjust above the tabs parts in tension. The plug drives the fingersoutwardly by pushing them along a ramp against an opposing spring force.The plug clears the tabs as the tabs are driven outwardly on respectiveramps such that the tabs are precluded to enter the bore as the plugclears. The drift dimension in the mandrel is preserved when the plugclears.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the collet fingers showing the supporttabs at the downhole ends;

FIG. 2 is a section view of the packer setting tool before the packer isset;

FIG. 3 is a detailed view of one of the collet fingers showing thepreferred parting location;

FIG. 4 is an end view of the collet finger shown in FIG. 3;

FIG. 5 is a close up view in section of the plug landed on the tabsbefore the packer is set;

FIG. 6 is the view of FIG. 5 with the packer set.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The setting sleeve assembly 10 is slidably mounted over the mandrel 12such that spaced fingers 14 each having tabs 16 that extend radiallyinto bore 18 of mandrel 12. A pair of wings 20 and 22 straddlelongitudinal openings 24 to allow the tabs 16 to extend into bore 18 toserve as support for a setting object such as a plug 26 as shown in FIG.2. The assembly 10 interacts with a known compression set packer that isnot shown. Shoulder 28 is intended to schematically represent aninteraction with a setting sleeve of a known packer that is not shown.Movement of the assembly 10 in the direction of arrow 30 under the forceof pressure on plug 26 from uphole results in parting at location 32 atthe lower end of fingers 14. Assembly 10 initially moves to extend slipsand seal of known compression set packer. As contact is made to thesurrounding tubular further movement of assembly 10 is arrested andtensile stress begins to build in fingers 14 until the yield limit isreached and separation occurs at necked down location 32 where stressconcentrated by design so that the break can occur at that locationafter the packer sets. With pressure continuing to be applied to theplug 26 that abuts the now unsupported tabs 16 on segments 34 nowdetached from respective fingers 14 the net result is that the plug 26advances the segments 34 with great force causing them to each approacha respective ramp 36. Each of the segments has an exterior groovesegment 38 such that all the groove segments 38 line up to accept a bandspring 40. As the plug 26 causes the break at 32 the segments 34 areaccelerated toward ramp 36 and tabs 16 retract radially until the plug26 can pass. However, the segments 34 have enough momentum to continueto radially expand the spring 40 and to pass the top 42 of the ramp 36.At that point the spring 40 pushes the segments 34 radially towardlongitudinal axis 44 until tabs 20 and 22 land on an outer surface ofthe mandrel 12 at opposed sides of openings 24 and on an opposite sideof ramp 36 from the run in position so that the end position of the tabs16 is such that the drift diameter of bore 18 is not reduced. The packeris now set and the plug 26 can either be caught in a catcher that is notshown, allowed to go to hole bottom or can be allowed to simplydisintegrate over time such as when the plug is made of a controlledelectrolytic material.

It should be noted that the plug 26 does not need to seal in bore 18 butsimply to allow pressure to build behind it to move the assembly 10. Theplug can be cylindrical or spherical or other shapes. Once the partedsegments run past the ramp they are prevented from going in the reversedirection by the band spring 40 or equivalent designs such as a snapring, a wedging action, a ratchet locking mechanism or the like. Thetabs that supported the plug are retracted far enough to get out of themain mandrel bore so as not to reduce its drift diameter. Although fourcollet fingers are shown additional or fewer fingers can be used. Whilethe wings 20 and 22 of adjacent fingers are shown spaced apart they canbe adjacent to provide nearly continuous support for the band spring 40.The location for the break in the fingers in tension can be accomplishedwith a reduction in width or thickness or both or by drilling holes orproviding a score that extends transversely.

The above description is illustrative of the preferred embodiment andmany modifications may be made by those skilled in the art withoutdeparting from the invention whose scope is to be determined from theliteral and equivalent scope of the claims below:

I claim:
 1. A subterranean compression set packer setting assembly for apacker comprising a sealing element and at least one slip, comprising: amandrel having a passage therethrough, said passage having a driftdimension, said mandrel comprising ends for attachment to a tubularstring; a setting sleeve on said mandrel and extending at least in partthrough at least one wall opening in said mandrel to present at leastone movable support in said passage; said setting sleeve movable withpressure applied to an object passing through said drift dimension andlanded on said support in said passage to set said seal and slip.
 2. Theassembly of claim 1, wherein: said support movable in said passage toretract from a central axis of said passage to beyond said driftdimension.
 3. The assembly of claim 1, wherein: said object displacessaid support axially.
 4. The assembly of claim 1, wherein: said objectdisplaces said support radially.
 5. The assembly of claim 1, wherein:said at least one support comprises a plurality of supports eachextending through a respective said opening.
 6. The assembly of claim 5,wherein: said supports are circumferentially spaced.
 7. The assembly ofclaim 1, wherein: said setting sleeve comprises a plurality of axiallyextending fingers at least some of which further comprise a said supportadjacent an end thereof
 8. The assembly of claim 7, wherein: saidsupports separating from said associated fingers to create segments onrising tensile stress in said associated fingers resulting from forcetransfer from said object to said supports when further movement of saidsleeve is impeded by setting the slip and seal of the packer.
 9. Theassembly of claim 7, wherein: said fingers mounted outside said mandrelwith said supports extending through respective said openings, saidsupports further comprise opposed wings to limit travel of said supporttoward a center of said passage.
 10. The assembly of claim 9, wherein:said mandrel comprises at least one ramp to engage at least one of saidwings to retract said supports outside said drift dimension.
 11. Theassembly of claim 8, wherein: said fingers comprising a feature toconcentrate tensile stress to define a separation location for saidsegments.
 12. The assembly of claim 11, wherein: said concentratingtensile stress feature comprises at least one of a score, openings,reduced dimension and slots.
 13. The assembly of claim 11, wherein: saidsegments are radially biased toward an axis of said passage.
 14. Theassembly of claim 13, wherein: said bias comprises a band spring. 15.The assembly of claim 13, wherein: said object pushes said segments on aramp to retract said segments to allow said object to pass; said radialbias on said segments biasing said segments toward the axis of saidpassage after said segments clear said ramp such that said segments arepositioned outside said drift dimension.
 16. The assembly of claim 15,wherein: said ramp configured to preclude return movement of saidsegments after initial movement over said ramp.
 17. The assembly ofclaim 1, wherein: said object does not seal pressure when landed on saidsupport.
 18. The assembly of claim 7, wherein: said fingers extend froma base ring whose movement sets the seal and slip of the packer.
 19. Theassembly of claim 15, wherein: said fingers mounted outside said mandrelwith said supports extending through respective said openings, saidsupports further comprise opposed wings to limit travel of said supporttoward a center of said passage.